Universal Plug and Play (UPnP™) technology defines an architecture for pervasive peer-to-peer network connectivity of intelligent appliances, wireless devices, and PCs of all form factors. It is designed to bring easy-to-use, flexible, standards-based connectivity to ad-hoc or unmanaged networks whether in the home, in a small business, public spaces, or attached to the Internet. UPnP technology provides a distributed, open networking architecture that leverages Transmission Control Proto/Internet Protocol (TCP/IP) and the Web technologies to enable seamless proximity networking in addition to control and data transfer among networked devices.
The UPnP Device Architecture (UDA) is designed to support zero-configuration, “invisible” networking, and automatic discovery for a breadth of device categories from a wide range of vendors. This means a device can dynamically join a network, obtain an IP address, convey its capabilities, and learn about the presence and capabilities of other devices. UPnP uses the Simple Service Discovery Protocol (SSDP) for service discovery. SSDP is generally built on top of Internet Protocol (IP) based networks, and uses User Datagram Protocol (UDP) multicasts of eXtensible Markup Language (XML) formatted service descriptions.
Although UPnP is a well known example of a technology for establishing ad-hoc, peer-to-peer networks, it is not the only one. Another example is known as Bonjour provided in products by Apple™. Bonjour is Apple's trade name for its implementation of Zeroconf (standing for Zero Configuration Networking), which provides network formation and service discovery on a local area network. The Bonjour technology is widely used throughout Mac OS X™ and allows users to set up a network without any configuration. Currently it is used by Mac OS X (and other operating systems) to find printers and file sharing servers.
These ad-hoc, peer-to-peer technologies are used to form networks and discover services offered on the networks. Most service discovery, schemes provide a way to uniformly describe services available. In UPnP, this is known as the Description phase, and involves passing specially formatted extensible Markup Language (XML) documents that describe available devices and services. The descriptions may include vendor-specific device information like the model name and number, serial number, manufacturer name, URLs to vendor-specific web sites, etc.
The vendor-specific device data provided in device descriptions is usually informational, but may not be needed to ultimately use the device via the network. For example a Network Attached Storage (NAS) is a standalone, special purpose computer that serves as a network file server. Therefore, if service discovery determines that a NAS device supports a known protocol (e.g., Windows™ file sharing), then the model and serial number of the device may not be important to using the NAS.
Similarly, other useful technical data may be provided in the device description, such as that the device utilizes two Serial Advanced Technology Attachment (SATA) hard drives in a mirrored Redundant Arrays of Independent Disks (RAID) configuration, and can be configured to hold up to six hard drives. This information may be useful to some users, and may be available elsewhere (e.g., owner's manual). Nonetheless, most devices that access the device may reasonably ignore such information, as it does not affect the ultimate file server interactions with the NAS.
As home networked products become more ubiquitous, the selection of products compatible with those networks may become more difficult. When properly selected, devices that interact via ad-hoc, peer-to-peer networks can be set up and run more easily that traditional networking products. However, if the products are not strictly compatible with the specific ad-hoc, peer-to-peer protocols or network hardware, then such the benefits of this type of networking technology cannot be realized. There is benefit, then, in helping users to assure that a newly purchased product will be “out of the box” compatible with a home network.